Retardation of non-thermal photon light curves from flaring blazars

Eichmann, B.; Schlickeiser, R.; Rhode, W.

doi:10.1051/0004-6361/200912966

Cited by 8 publications

(7 citation statements)

References 15 publications

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“…Nonetheless, this will lead to the increased number of parameters and a reasonable conclusion on the physical condition responsible for the flare cannot be derived. Again, we have not considered the light travel time effects [52,53,54,55] since the flare time scale at the source frame (t of ∼ 1 day in observer frame, the corresponding time in source frame will be…”

Section: Discussionmentioning

confidence: 99%

A time dependent approach to model X-ray and γ–ray light curves of Mrk 421 observed during the flare in February 2010

et al. 2017

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A time dependent approach to model X-ray and γ-ray chrotron self Compton emission process. To model the observed X-ray and γ-ray light curves, we numerically solve the kinetic equation describing the evolution of particle distribution in the emission region. The injection of particle distribution into the emission region, from the putative acceleration region, is assumed to be a time dependent power law. The synchrotron and synchrotron self Compton emission from the evolving particle distribution in the emission region are used to reproduce the X-ray and γ-ray flares successfully. Our study suggests that the flaring activity of Mrk 421 can be an outcome of an efficient acceleration process associated with the increase in underlying non-thermal particle distribution.

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Section: Discussionmentioning

confidence: 99%

A time dependent approach to model X-ray and γ–ray light curves of Mrk 421 observed during the flare in February 2010

et al. 2017

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“…Thus, the minimal variability time scale, which is possible at all, is given by the light-crossing time scale, since the source is evenly contributing to the radiative output. If the source only partially radiates, the variability time scale can be much lower (Eichmann et al 2010). The rising phase until λ 0 is dominated by the source geometry, giving a t 2 -dependence up to the break times t 2 (ǫ) for α ≪ 1 and t 4 (ǫ) for α ≫ 1, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…We include this retardation effect, but assume that the source is (i) spatially homogeneous, and (ii) optically thin. For optically thin sources all photons can leave the emission region without further spatial diffusion (Eichmann et al 2010). Then the received intensity is just a function of the distance l of the production site from the front.…”

Section: Geometry Of the Situationmentioning

confidence: 99%

Synchrotron Lightcurves of Blazars in a Time-Dependent Synchrotron-Self Compton Cooling Scenario

Zacharias

Schlickeiser

2013

ApJ

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Blazars emit non-thermal radiation in all frequency bands from radio to γ-rays. Additionally, they often exhibit rapid flaring events at all frequencies with doubling time scale of the TeV and X-ray flux on the order of minutes, and such rapid flaring events are hard to explain theoretically. We explore the effect of the synchrotron-self Compton cooling, which is inherently time-dependent, leading to a rapid cooling of the electrons. Having discussed intensively the resulting effects of this cooling scenario on the spectral energy distribution of blazars in previous papers, the effects of the time-dependent approach on the synchrotron lightcurve are investigated here. Taking into account the retardation due to the finite size of the source and the source geometry, we show that the time-dependent synchrotronself Compton (SSC) cooling still has profound effects on the lightcurve compared to the usual linear (synchrotron and external Compton) cooling terms. This is most obvious if the SSC cooling takes longer than the light crossing time scale. Then in most frequency bands the variability time scale is up to an order of magnitude shorter than under linear cooling conditions. This is yet another strong indication that the time-dependent approach should be taken into account for modeling blazar flares from compact emission regions.

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“…We should also note that our discussion adopts a point-like emission zone, which means that we neglect additional effects from photon retardation variability processes from the finite size of the emission zone. For an extended analysis of these effects we refer to the discussion in Eichmann et al (2010Eichmann et al ( , 2012.…”

Section: Discussionmentioning

confidence: 99%

External Compton Emission in Blazars of Nonlinear Synchrotron Self-Compton-Cooled Electrons

Zacharias

Schlickeiser

2012

ApJ

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The origin of the high-energy component in spectral energy distributions (SED) of blazars is still a bit of a mystery. While BL Lac objects can be rather successfully modeled within the one-zone synchrotron self-Compton (SSC) scenario, the SED of low peaked Flat Spectrum Radio Quasars (FSRQ) is more difficult to reproduce. Their high-energy component needs the abundance of strong external photon sources, giving rise to stronger cooling via the inverse Compton channel, and thusly to a powerful component in the SED. Recently, we were able to show that such a powerful inverse Compton component can also be achieved within the SSC framework. This, however, is only possible if the electrons cool by SSC, which results in a non-linear process, since the cooling depends on an energy integral over the electrons. In this paper we aim to compare the non-linear SSC framework with the external Compton (EC) output by calculating analytically the external Compton component with the underlying electron distribution being either linearly or non-linearly cooled. Due to the additional linear cooling of the electrons with the external photons, higher number densities of electrons are required to achieve non-linear cooling, resulting in more powerful inverse Compton components. If the electrons initially cool non-linearly, the resulting SED can exhibit a dominating SSC over the EC component. However, this dominance depends strongly on the input parameters. We conclude that with the correct time-dependent treatment the SSC component should be taken into account to model blazar flares.

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Retardation of non-thermal photon light curves from flaring blazars

Cited by 8 publications

References 15 publications

A time dependent approach to model X-ray and γ–ray light curves of Mrk 421 observed during the flare in February 2010

A time dependent approach to model X-ray and γ–ray light curves of Mrk 421 observed during the flare in February 2010

Synchrotron Lightcurves of Blazars in a Time-Dependent Synchrotron-Self Compton Cooling Scenario

External Compton Emission in Blazars of Nonlinear Synchrotron Self-Compton-Cooled Electrons

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